Good questions.
I hope we see a move away from the Diorama style. I suppose its a personal taste thing, but they've begun to look so contrived; like bad special effects in a movie. I'd also like to see a greater emphasis on the use of plants and varieties, much of the contest has leaned heavily on hardscape and few plant species. Maybe this is an issue with scoring or with the styles that do well. To that point, you are right, dutch scapes do not score well. To some extent I understand why, they do not show off much of a natural environment with their heavily manicured look. They also lack a sense of depth and scale you can achieve with other style layouts. Nanos suffer as well, but for different reasons. While you can achieve great sense of depth or scale, you are greatly limited on plant selection in order to achieve it so there are losses to the overall look in that regard. I think the ideal scape is a 120 cm. Much bigger and you get a big look because its a big tank...more easily achieved. Smaller and you lose some options or flexibility to achieve various effects or looks which hurt the scoring.
Who will take Amano's place? Can anyone? I'm not sure we will see someone rise to take his place or try to fill his shoes. We may see more of an IAPLC or ADA run by committee with the goal of continuing Mr. Amano's vision. I'm far from knowledgeable in this so this is just a guess...
As far as reverse engineering...I think if you wanted the look in your home you can do so to some extent. Acquiring the hardscape and understanding some of the skills required to assemble it in the ways they do would be some of the most difficult parts. If you can grow plants well that is.
We have a great interview with Steven Chong of the Tokyo Aquascaping Union coming up in The Aquascaping Podcast, where he talks about competition focused Aquascaping. There is a big difference in the mindset and approach as opposed to most of us hobbyists who tend to make scapes we like or want in our living room and then submit to a contest if we feel it is good enough and the competitive contest focused aquascaper whose goal is to create a winning layout. Stay tuned...should be up in a couple weeks